A histogram is a chart that shows frequencies for equal width intervals of values of a metric variable. A company wants to know how monthly salaries are distributed over 1,110 employees having operational, middle or higher management level jobs. The screenshot below shows what their raw data look like.
The snowflake schema is a variation of the star schema, featuring normalization of dimension tables. In computing, a snowflake schema is a logical arrangement of tables in a multidimensional database such that the entity relationship diagram resembles a snowflake shape. The snowflake schema is represented by centralized fact tables which are connected to multiple dimensions..
Star and Snowflake Schemas. In relational implementation, the dimensional designs are mapped to a relational set of tables. A star schema model can be depicted as a simple star: a central table contains fact data and multiple tables radiate out from it, connected by the primary and foreign keys of the database.